Telephone transmitter



TELEPHONE TRANSMITTER Filed April 18 19724 @H501 we@ Fatented Sept. ll, 1926.

ieaeei l r si.

WILLIAM-I. SHERROD, OF LOS ANGELES, CALIFORNIA.

TELEPHGNE TRANSIVIITTER.

Application filed .Apr1.18, 1924. Serial No. 707,516.

My invention relates to telephone transmitters and particularlyv pertains to a mouthpiece therefor.'

An object of my invention is to provide a mouthpiece for telephone transmitters and the like which is so constructed as to afford a means for amplifying the sounds delivered therethrough to the transmitter diaphragm whereby the sound will be intensified at the receiver and rendered more clear and distinct than with the ordinary mouthpieces.

TVVith the foregoing object in view, together with such other objects and advantages as may subsequently appear, the .invention is illustrated in the accompanying drawing, in which- Figure 1 is a fragmentary front elevational view of a telephone transmitter fitted with my improved mouthpiece.

Figure 2 is a view in side elevation of the parts shown in Figure 1.

Figure 3 is a vertical cross sectional view as seen on the line 3-3 of Figure 1, with arts shown in elevation and partially roken away and shown in section.

Figure 4 is a sectional elevational view as seen on the line llll of Figure 3.

Referring to the drawings more speciiically, 5 indicates a telephone transmitter case which is fittedwith a cap` G having a central threaded bore in which the threaded end 8 of a mouthpiece body 9 is screwed and ythereby securely held on the cap.

The general outline of thek mouthpiece body 9 has the same appearance as a standard mouthpiece used on telephones, heilig flared outwardly from a shoulder 10 joining the threaded end 8 to its outer edge 11.

The interior wall surface 12 of the outer portion of the mouthpiece tapers or converges inwardly and intersects a substantially frusto-conoidal projection 13 that extends outwardly into the space or chamber 14 surrounded by the wall surface 12 and terminates in spaced relation to the outer end of the mouthpiece; the projection 13 being here shown as formed integral with the mouthpiece structure. The side walls of the projection 13 are preferably curved longitudinally and intersect the wall surface 12 on a curve, as indicated at 15. The projection 13 is .formed with an axial opening or passage 16 which leads from the chamber 14 to the inner end of the mouthpiece to the space 17 interiorly of the case 5 in front of the usual diaphragm 18. The passage 16 is Venturi-shaped; the outer walls of the passage converging from the outer end of the projection 13 to a restricted throat 19 located within the projection 13 close to its louter end, and the passage being fiared outwardly from the throat 19 to form a trumpet-shaped chamber 2O that opens in close proximity to the diaphragm 8. The inner open end of the passage 16 is of a diameter exceeding that of the outer open end thereof; being here shown as of a diameter substantially equal to that of the outside wall of the projection 13 at the point where it intersects the curved end wall of the chamber 14.

Mounted in the chamber 14 in spaced relation to the projection 13 is a concave-con- Vex disk 21, the perimeter of which is spaced from the wall surface 12 of the mouthpiece body; the dislr being held in place by a series of pins 22 that are suitably anchored in the dislr and mouthpiece. The disk is ar-` ranged with its concave side 23 facing the chamber 14: so as to operate to direct soundwaves into the Venturi-shaped passage 16.

it has been found in practice that sound waves entering the mouthpiece and directed into the passage 16 will be amplified by reason of the Venturi shape of the latter before reaching the diaphragm 18, thereby intensifying the sounds transmitted by the telephone so as to render them more audible at the receiver.

I ,claim:-

1. ln a telephone transmitter, a mouthpiece formed with a convergentinner wall surface and having a frusto-conical projection extending into a space surrounded by said wall surface, said projection being formed with an axial passage having outwardly flared end portions.

2; ln a telephone transmitter, a mouthpiece formed with a convergent inner wall surface and having a frusto-conical projection extending into a space surrounded by said wall surface, said projection being formed with an axial passage having out-l wardly fiared end portions, and a disk positioned in front of the outer end of said project-ion having a concave face extending toward the latter.

3. In a telephone transmitter, a mouthpiece formed with a convergent inner wall surface, a frusto-conical projection extending into the space surrounded by said wall surface axially of the mouthpiece, the external Wall surface of which intersects and is formed in continuation of said convergent inner Wall surface, said projection being formed with an axial passage having a re.- stricted throat located close to the outer end of the projection and being flared outwardly from the throat forming a trumpet shaped chamber opening to the inner end of the mouthpiece, and a concave-convex disc spaced forwardly of said projection with its concave surface presented thereto, said disc being supported on the mouth piece Wall and spaced throughout its perimeter therefrom'.

WILLIAM H. SHERROD. 

